Objective. This study documents the measurement properties of a brief, self-administered questionnaire of disease signs and symptoms in patients with rheumatoid arthritis.
Methods. The Rapid Assessment of Disease Activity in Rheumatology (RADAR) questionnaire assesses joint pain/tenderness and clinical status. One hundred ninety-three pairs of RADAR forms were completed by 45 subjects and their assigned clinician evaluators.
Results. Subject—clinician agreement (intraclass correlation coefficients [ICC]) for joint pain/tenderness and clinical status ranged from 0.52 to 0.87 (P = 0.0001), with 83% ≥0.65. The ICC for change in joint scores over 6 months was 0.83 (P = 0.0001).
Conclusion. The 2-page RADAR questionnaire produces valid estimates of joint count and clinical status that are sensitive to change.